Photographic processes and products



United States Pate t 7 Claims. (Cl. 96-29) This invention relates to photography and more particularly to products and processes for the development of photosensitive silver halide elements.

It is a primary object of the present invention to provide novel diffusion-transfer photographic processes and products whereby improved control of the transfer of mobile dye developer to an image-receiving layer may be obtained.

A further object of the present invention is to provide novel photographic processes and products for obtaining color images by a diffusion-transfer process wherein a dye developer is initially present in the form of a hydrolyzable derivative of said dye developer and wherein said hydrolyzable derivative is subjected to hydrolysis during processing.

A still further object of the present invention is to provide novel photographic processes and products wherein a hydrolyzable derivative of a dye developer is employed and said derivative is of relatively low mobility until hydrolysis occurs.

A still further object of the present invention is to provide photographic processes and products wherein hydrolyzable derivatives of dye developers are employed, said derivatives being initially nonreactive with an associated photosensitive silver halide emulsion and rendered reactive by hydrolysis occurring during processing. a

A still further object of the present invention is to provide photographic processes and products for use in monochromatic and multi-color diffusion-transfer processes utilizing hydrolyzable derivatives of dye developers, which derivatives contain groups removable during photographic processing, to provide thereby improved color rendition.

A still further object of the present invention is to provide novel processes for the development of silver halide emulsions, in which the novel developing agent is capable of developing a latent image and imparting a positive colored image of said latent image to a superposed image-receiving layer.

A still further object of the present invention is to provide novel photographic processes and products for obtaining color images by diffusion-transfer processes which employ hydrolyzable derivatives of dye developers, which derivatives comprise the hydrolyzable carbalkoxy and carbaryloxy esters of specified dye developers.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the product possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description.

The compounds employed in the present invention possess the properties of both a dye and, during the photographic processes herein disclosed, a developing agent; thus they may be referred to as dye developer precursors. The nature of these dye developer precursors will be described hereinafter.

Patented Jan. 18 1966 The photographic processes and compositions disclosed herein are particularly useful in the treatment of a latent image present in a photosensitive element, such as an exposed silver halide emulsion, whereby a positive dye image thereof may be imparted to another element, herein referred to as an image-carrying or image-receiving element.

The copending application of Howard G. Rogers, Serial No. 748,421, filed July 14, 1958 (now US. Patent No. 2,983,606, issued May 9, 1961), a continuation-in-part of Serial No. 415,073, filed March 9, 1954 (now abandoned), discloses diffusion-transfer reversal processes wherein a photographic negative material such as a photographic element comprising an exposed silver halide emulsion layer containing a latent image, is processed to impart to an image-receiving element a reversed or positive dye image of said latent image by permeating into said emulsion layer a suitable liquid processing composition and bringing said emulsion layer into superposed relationship with an appropriate image-receiving layer. It is an object of this invention to provide additional compounds suitable for use in such processes.

In carrying out the process of this invention, a photosensitive element containing a silver halide emulison is exposed and Wetted with a liquid processing composition, for example, by immersing, coating, spraying, flowing, etc., in the dark, and the photosensitive element superposed, prior to, during or after wetting, on a sheet-like support element, which may be utilized as an imagereceiving element. In a preferred embodiment, the photosensitive element contains a layer of dye developer precursor, and the liquid processing composition is applied to the photosensitive element in a uniform layer as the photosensitive element is brought into superposed position with an image-receiving element. It is also within the scope of this invention to apply the liquid processing composition prior to exposure, in accordance with the disclosure in the copending application of Edwin H. Land, Serial No. 498,672, filed April 1, 1955 (now US. Patent No. 3,087,816, issued March 7, 1963). The liquid processing composition permeates the emulsion to provide a solution of dye developer substantially uniformly distributed therein. As the latent image is developed, the oxidation product of the dye developer is immobilized or precipitated in situ with the developed silver, thereby providing an imagewise distribution of unoxidized dye developer dissolved in the liquid processing composition. This immobilization is apparently, at least in part, due to a change in the solubility characteristics of the dye developer upon oxidation, and especially as regards its solubility in alkaline solutions. It may also be due, in part, to a tanning effect on the emulsion by the oxidized developing agent and to localized exhaustion of alkali due to development. At least part of this imagewise distribution of unoxidized dye developer is transferred, by im bibition, to a superposed image-receiving layer or element, said transfer substantially excluding silver or oxdized dye developer. Under certain circumstances, the layer of the liquid processing composition may be utilized as the image-receiving layer. The latter element receives a depthwise diffusion, from the emulsion, of unoxidized dye developer without appreciably disturbing the imagewise distribution thereof to provide a reversed or positive, colored image of the developed image. The image-receiving element may contain agents adapted to mordant or otherwise rlx the diliused, unoxidized dye developer. If the color of the diffused dye developer is affected by changes in the pH of the image-receiving element, this pH may be adjusted in accordance with well-known techniques to provide a pH affording the desired color. Imbibition periods of approximately one minute have been found to give good results, but this contact period may be adjusted where necessary to compensate for variations in temperature or other conditions. The desired positive image is revealed by stripping the image-receiving element from the photosensitive element at the end of the imbibition period.

The compounds of the present invention may be utilized in the photosensitive element, for example in, on or behind the silver halide emulsion, or they may be utilized in the image-receiving element. In a preferred embodiment, a coating or layer of the compound is placed behind the silver halide emulsion, i.e., on the side of the emulsion adapted to be located most distant from the photographed subject when the emulsion is exposed and preferably also adapted to be most distant from the image-receiving element when in superposed relationship therewith. Placing the dye developer hydrolyzable derivative behind the emulsion layer, as in the preferred embodiment, has the advantage of providing increased contrast in the positive image, and also minimizes any light-filtering action by the colored dye developer. In this preferred embodiment, the layer of dye developer hydrolyzable derivative may be applied by using a coating solution containing about 0.5 to 8% by weight, of the derivative.

The liquid processing composition above referred to comprises at least an aqueous solution of an alkaline com pound, for example, diethylamine, sodium hydroxide or sodium carbonate, and may contain the dye developer. In some instancs, it may contain an auxiliary or accelerating developing agent. If the liquid processing composition is to be applied to the emulsion by being spread thereon, preferably in a relatively thin, uniform layer, it may also include a viscosity-increasing compound comprising a film-forming material of the type which, when said composition is spread and dried, will form a relatively firm and relatively stable film. A preferred filmforming material is a high molecular weight polymer such as a polymeric, water-soluble ether inert to an alkali solution, as for example, a hydroxyethyl cellulose or sodium carboxymethyl cellulose. Other film-forming materials or thickening agents whose ability to increase viscosity is substantially unaffected when left in solution for a long period of time may also be used.

The copending application of Edwin H. Land and Howard G. Rogers, Serial No. 669,542, filed July 2, 1957 now abandoned, the subject matter of which has been incorporated in Serial No. 194,359, filed May 14, 1962, discloses diffusion-transfer processes of the previously disclosed type which employ dye developers in the form of hydrolyzable derivatives thereof. These hydrolyzable derivatives are disclosed to be initially less mobile and thus prevent premature transfer of dye developer which might give rise to highlight stain and/ or incomplete color separation. The present application is principally concerned with novel dye developer hydrolyzable derivatives particularly applicable for use in the processes therein disclosed.

The dye developer precursors of the present invention comprise dyes, preferably azo, anthraquinone, indophenol, indoaniline, and azomethine dyes, characterized in that they contain not less than one and not more than two groups selected from the group consisting of the carbalkoxy and carbaryloxy monoand diesters of orthoand para-dihydroxyphenyl groups and halogen and alkyl substituted derivatives thereof.

The last-mentioned novel hydrolyzable dye developer derivatives also may be represented by the formula:

wherein D represents a dye system, that is, an auxochromophoric system, preferably an azo, anthraquinone, indophenol, indoaniline or azomethine dye system; Y is a covalent bond or a divalent radical; a is 1 or 2; and Z is a group selected from the group consisting of the carbalkoxy and carbaryloxy mono and diesters of ortho and para-dihydroxyphenyl groups and halogen and alkyl substituted derivatives thereof. x

As examples of divalent radicals, signified by the term Y, suitable for use in the practice of the present invention, mention may be made of: divalent organic radicals such as alkylene radicals, preferabl y' lower alkylene radicals such as ethylene, isopropylene, sulfonamido; sulfamyl; carboxamido; carbamyl; arylenr? radicals such as phenylene, etc., aralkylene radicals such fl phenethyl etc.; acyl radicals such as and divalent radicals which contain both hetero and carbon atoms as constituent components, as for example,

A preferred group of compounds of the present invention comprise the hydrolyzable dye developer derivatives of the formula:

Anthraquinone- Y wherein each R is an alkyl or aryl group; a has the same significance as previously set forth; and Y is an alkylene group, preferably a lower alkylene group such as, methylene, ethylene, propylene, trimethylene, etc.

In addition to the substituents specifically designated on the phenyl nucleus of the aforementioned generic formula, the phenyl nucleus may be substituted by halogen, alkoxy, alkyl, etc., radicals, that is, radicals so substituted as not to impair the respective silver halide developing function of the phenyl group when said group is subjected to hydrolysis by the photographic processing composition.

The novel dyes of the present invention may be prepared by reacting a dye developer, preferably an azo, anthraquincne, indophenol, indoaniline, or azomethine dye developer, having not less than one and preferably not more than two ortho-dihydroxyphenyl or para-dihydroxyphenyl groups and halogen and alkyl substituted derivatives thereof with an alkyl and/or an aryl haloformate such as a bromoor chloroformate, preferably a chloroformate. Where the dye developer has additional available reactive hydroxyl groups, reaction may occur at such additional groups.

The variance of the mole ratios of reactants, that is, the mole ratios of the respective haloformate to dye developer molecule provides either the desired monoor bis-esters of the dihydroxybenzene nuclei or mixtures thereof. A decrease in the mole ratio of the respective haloformate to dye developer molecule effects an increased formation of the mono-ester.

As examples of suitable haloformates useful in the practice of the present invention, mention may be made of: methyl chloroformate, ethyl chloroformate, n-propyll chloroformate, n-butyl chloroformate, n-amyl chloro formate, n-hexyl chloroformate, Z-ethylhexyl chloroformate, dodecyl (lauryl) chloroformate, octadecanyl (stearyl) chloroformate, benzyl chloroformate, phenyl chloroformate, naphthyl chloroformate, etc.

The preparations of numerous of the dye developers preferred for use in synthesizing dye developer precursors of the present invention are set forth in the following copending U.S. applications:

Serial No. 445,171, filed July 22, 1954, in the name of Richard S. Corley, now abandoned;

Serial No. 449,514, filed August 12, 1954, in the names of Elkan R. Blout and Myron S. Simon, now abandoned;

Serial No. 471,542, filed November 26, 1954 in the names of Elkan R. Blout, Saul G. Cohen, Milton Green, Howard G. Rogers, Myron S. Simon, and Robert B. Woodward, now abandoned, the subject matter of which has been incorporated in Serial No. 1,442 and Serial No. 1,443, both filed January 11, 1960, the former in turn now abandoned, the subject matter of which has been incorporated in Serial No. 401,714, filed October 5, 1964;

Serial No. 473,458, filed December 6, 1954, in the names of Elkan R. Blout, Saul G. Cohen, Milton Green, and Myron S. Simon (now U.S. Patent No. 3,077,402, issued February 12, 1963);

Serial No. 478,922, filed December 30, 1954, in the names of Elkan R. Blout, Marilyn R. Cohler, Milton Green, Myron S. Simon and Robert B. Woodward, now abandoned, the subject matter of which has been incorporated in Serial No. 824,785 and Serial No. 824,786, both filed July 3, 1959, now abandoned, the subject matters of which have been incorporated in, respectively, Serial No. 233,461, filed October 26, 1962 (now U.S. Patent No. 3,135,606, issued June 2, 1964), and Serial No. 318,827, filed October 25, 1963;

Serial No. 485,342, filed January 31, 1955, in the name of Richard S. Corley (now U.S. Patent No. 2,983,603, issued May 9,1961);

Serial No. 485,840, filed February 3, 1955, in the names of Elkan R. Blout and Howard G. Rogers;

Serial No. 521,874, filed July 13, 1955, in the names of Elkan R. Blout, Milton Green, Myron S. Simon, and Howard G. Rogers, now abandoned, the subject matter of which has been incorporated in Serial No. 799,427, filed March 16, 1959 (now US. Patent No. 3,076,820, issued February 5, 1963);

Serial No. 522,848, filed July 18, 1955, in the names of Elkan R. Blout, Sydney Kasman and Myron S. Simon, now abandoned, the subject matter of which was incorporated in Serial No. 799,425, filed March 16, 1959 (now U.S. Patent No. 3,076,808, issued February 5, 1963);

Serial No. 612,045, filed September 25, 1956, in the names of Elkan R. Blout, Milton Green and Howard G. Rogers, now abandoned, the subject matter of which has been incorporated in Serial No. 144,816, filed October 18, 1961 (now U.S. Patent No. 3,134,672, issued May 26, 1964);

Serial No. 612,052, filed September 25, 1956, in the names of Milton Green and Howard G. Rogers, now abandoned, the subject matter of which has been incorporated in Serial No. 165,930, filed January 12, 1962 (now U.S. Patent No. 3,135,604, issued June 2, 1964) Serial No. 612,053, filed September 25, 1956, in the name of Myron S. Simon, now abandoned, the subject matter of which has been incorporated in Serial No. 196,523 and Serial No. 196,524, both filed May 21, 1962 (the former now U.S. Patent No. 3,183,089, issued May 11, 1965, the latter now U.S. Patent No. 3,134,765, issued May 26, 1964);

Serial No. 612,054, filed September 25, 1956, in the names of Helen P. Husek and Myron S. Simon, now abandoned, the subject matter of which has been incorporated in Serial No. 197,259 and Serial No. 197,283, both filed May 24, 1962 (the former now U.S. Patent No. 3,134,763, issued May 26, 1964);

Serial No. 612,055, filed September 25, 1956, in the name of Helen P. Husek, now abandoned, the subject matter of which has been incorporated in Serial No. 192,354, and Serial No. 192,355, both filed May 4, 1962 (the former now U.S. Patent No. 3,134,762, issued May 26, 1964);

Serial No. 663,905, filed June 6, 1957, in the names of Milton Green and Howard G. Rogers, now abandoned, the subject matter of which has been incorporated in Serial No. 193,293 and Serial No. 193,326, both filed May 8, 1962 (the former now U.S. Patent No. 3,173,906, issued March 16, 1955);

Serial No. 669,969, filed July 5, 1957, in the name of Milton Green, now abandoned;

Serial No. 678,439, filed August 15, 1957, in the name of Myron S. Simon, now abandoned, the subject matter of which has been incorporated in SerialNo. 232,584 and Serial No. 232,585, both filed October 23, 1964 (the former now U.S. Patent No. 3,131,061, issued April 28, 1964);

Serial No. 680,403, filed August 26, 1957, in the name of Milton Green, now abandoned, the subject matter of which has been incorporated in Serial No. 316,498, filed October 16, 1963;

Serial No. 680,434, filed August 26, 1957, in the name of Milton Green, now abandoned, the subject matter of which has been incorporated in Serial No. 230,287 and Serial No. 230,288, both filed October 12, 1962;

Serial No. 680,437, filed August 26, 1957, in the names of Elkan R. Blout and Myron S. Simon (now U.S. Patent No. 3,047,386, issued July 31, 1962);

Serial No. 680,619, file-d August 27, 1957, in the names of Elkan R. Blout and Myron S. Simon, now abandoned;

Serial No. 685,081, filed September 20, 1957, in the names of Elkan R. Blout, Milton Green, Howard G. Rogers, and Myron S. Simon, now abandoned, the subject matter of which has been incorporated in Serial No. 222,656 and Serial No. 222,702, both filed September 10, 1962 (the former now U.S. Patent No. 3,142,565, issued July 28, 1964);

Serial No. 703,515, filed December 18, 1957, in the name of Milton Green, now abandoned;

Serial No. 707,109, filed January 6, 1958, in the names of Elkan R. Blout, Milton Green, Howard G. Rogers and Robert B. Woodward, now abandoned;

Serial No. 709,001, filed January 15, 1958, in the names of Milton Green, Helen P. Husek and Sydney Kasman, now abandoned, the subject matter of which has been incorporated in Serial No. 206,639, filed June 7, 1962;

Serial No. 709,002, filed January 15, 1958, in the names of Milton Green and Helen P. Husek, now abandoned, the subject matter of which has been incorporated in Serial No. 75,128, filed December 12, 1960 (now U.S. Patent No. 3,158,595, issued November 24, 1964);

Serial No. 709,005, filed January 15, 1958, in the names of Sydney Kasman and Helen P. Husek, now abandoned, the subject matter of which has been incorporated in Serial No. 75,127, filed December 12, 1960, now abandoned, the subject matter of which has been incorporated in Serial No. 339,615, filed January 23, 1964;

Serial No. 711,811, filed January 29, 958, in the name of Milton Green, now abandoned, the subject matter of which has been incorporated in Serial No. 232,613, filed October 23, 1962;

Serial No. 748,145, filed July 14, 1958, in the names of Milton Green and Howard G. Rogers, now abandoned, the subject matter of which has been incorporated in Serial No. 190,804, filed April 27, 1962 (now U.S. Patent No. 3,186,982, issued June 1, 1965);

Serial No. 755,804, filed August 18, 1958, in the names of Elkan R. Blout, Saul G. Cohen, Milton Green and Myron S. Simon, now abandoned;

Serial No. 756,066, filed August 20, 8, in the name of Myron S. Simon, now abandoned;

Serial No. 771,719, filed November 4, 195 8, in the names of Elkan R. Blout and Richard S. Corley, now abandoned, the subject matter of which has been incorporated in Serial No. 193,320, filed May 8, 1962; and

Serial No. 788,893, filed January 26, 1959, in the names of Milton Green and Myron S. Simon, now abandoned,

the subject matter of which has been incorporated in Serial No. 359,998, filed April 15, 1964.

As examples of compounds contemplated within the scope of the present invention, mention may be made of the following: (1) -CO-CzH5 CH3 II 1 o NH-CH-CHpO (i O0CzH 1,4-bis-(,B-[2,5-di-(ethoxycarbonyloxy) phenyl]-amethyl-ethyl-amino) -anthraquinone 1 ,4-bis- 3- [2', 5 '-di- (n-butoxycarbonyloxy) -phenyl] -oz methyl-ethyl-amino)-anthraquinone NHC H-CE O I I 0 A I CH3 1,4-bis- (B-[2,5'-di- (n-hexyloxycarbonyloxy)-phenyl]-umethyl-ethyl-amino)-anthraquinone phere of nitrogen.

Example 1 0.538 gram (10 rnol.) of 1,4-bis-(,B-hydroquinonyl-amethyl-ethyl-amino)anthraquinone, the preparation of which is disclosed in the aforementioned copending application Serial No. 478,922 (now abandoned, the subject matter of which has been incorporated in Serial No. 824,785 and Serial No. 824,786, both filed July 3, 1959, in turn now abandoned, the subject matter of which has been incorporated in, respectively, Serial No. 233,461, filed October 26, 1962 [now US. Patent No. 3,135,606, issued June 2, 1964], and Serial No. 318,827, filed October 25, 1963) is dissolved in 10 cc. of purified, anhydrous dioxane which has been deaerated with nitrogen. 1 cc. of 1.015 N (10- rnol.) of sodium hydroxide is added to the solution in an atmosphere of nitrogen. 0.15 cc. (0.1645 gram, 10* mol.) of n-hexyl chloroformate is added to the solution. The resultant solution is stirred for 10 minutes, acidified with 10% hydrochloric acid, evaporated to dryness, and dried in a vacuum desiccator overnight over potassium hydroxide. The product is washed with ice water to yield 0.65 gram of a blue-black glistening crystalline solid, 1,4-bis- (fi- [2',5'-di- (n-hexyloxycarbonyloxy) -phenyl]-a-methyl-ethyl-amino)-anthraquinone. An infrared absorption spectrum of the product showed the presence of characteristic ester bonds at 1780 cm. and the absence of alcoholic hydroxyl group bonds.

Example 2 0.538 gram (10 mol.) of 1,4-bis-(fi-hydroquinonyla-methyl-ethyl-amino)-anthraquinone is dissolved in 10 cc. of purified, anhydrous dioxane which has been deaerated with nitrogen. 1 cc. of 1.015 N (10* mol.) of sodium hydroxide is added to the solution in an atmos- 0.13 cc. (0.137 gram) of n-butyl chloroformate is added to the solution. The resultant solution is stirred for 10 minutes and the solvent removed by evaporation. A yield of 0.6 gram of 1,4-bis-(,8-[2',5- di (n butoxycarbonyloxy)-phenyl]-a-methyl-ethyl-amino)-anthraquinone is obtained after Washing with ice water and drying.

Example 3 0.538 gram (10 mol.) of 1,4-bis-(B-hydroquinonyl-amethyl-ethyl-amino)-anthraquinone is dissolved with heating in cc. of purified, anhydrous dioxane which has been deaerated with nitrogen. 1 cc. of 1.015 N sodium hydroxide is added to the solution in an atmosphere of nitrogen. 0.318 gram (10 rnol.) of octadecanyl chloroformate is added to the solution. The resultant solution is stirred for 10 minutes in an atmosphere of nitrogen, acidified with 10% hydrochloric acid, evaporated to dryness, washed with ice water and dried in a vacuum desiccator over potassium hydroxide. The resultant product, 0.75 gram of 1,4 bis 3-[2',5'-di-(octadecanyloxycarbonyloxy) phenyl] 0c methylethyl-amino)-anthraquinone, exhibits a melting point at 92 to 117 C. An infrared absorption spectrum of the product showed the presence of characteristic ester bonds at 1780 cm. and the absence of alcoholic hydroxyl group bonds.

Example 4 0.538 gram (10* mol.) of 1,4-bis-(fi-hydroquinonylu-methyl-ethyl-amino)-anthraquinone is dissolved with heat in 10 cc. of purified, anhydrous dioxane which has been deaerated with nitrogen. 10 cc. of 0.1 N sodium hydroxide is added to the solution in an atmosphere of nitrogen. 0.108 gram (10 rnol.) of ethyl chloroformate is added to the solution. The resultant solution is heated on a steambath and swirled in an atmosphere of nitrogen, acidified With 10% hydrochloric acid, evaporated to dryness, washed with ice water and dried in a vacuum desiccator over potassium hydroxide. The yield com- 9 prised 0.45 gram of crystalline, 1,4-bis-(B-[2,5-di-(ethyloxycarbonyloxy) phenyl] a methyl-ethyl-amino)- anthraquinone.

Example A photosensitive element is prepared by coating a gelatin-coated film base with a solution containing 4% of 1,4 bis-(p-[2,5-di(n-hexyloxycarbonyloxy)-phenyl]- u-methyl-ethyl-amino)-anthraquinone (Formula 3 as prepared in Example 1), in a 4% solution of cellulose acetate hydrogen phthalate in a 50:50 mixture, by volume, of acetone and tetrahydrofuran. After this coating has dried, a silver iodobromide emulsion is applied. This photosensitive element is exposed and processed by spreading an aqueous liquid processing composition comprising:

Percent Sodium carboxymethyl cellulose 4.5 l-phenyl-3-pyrazolidone 0.2 Sodium hydroxide 2.5 Potassium bromide 0.2 G-nitrobenzimidazole 0.16 2,5-bis-ethyleneiminohydroquinone 0.6

between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprises a cellulose acetate-coated baryta paper which has been coated with a solution comprising N-methoxymethyl polyhexamethylene adipamide in 80% aqueous ethanol. After an imbibition period of approximately 1 minute, the image-receiving element is separated and contains a cyan positive dye image of the photographed subject.

Repetition of substantially the same procedure as set forth in Example 5, utilizing the dyes of Formulae l, 2 and 4, respectively, results in the formation, in the imagereceiving layer, of a reversed positive cyan dye image of the photographed subject.

In certain instances, the sensitivity of an associated silver halide emulsion may be affected by a reaction be tween the associated dye developer and a sensitizer employed in said silver halide emulsion, or by means of a displacement of sensitizing dye absorbed on the silver halide, resulting in decreased sensitivity. It has been found that the employment of the hydrolyzable derivatives of the present invention as precursors to the ultimately desired dye developers offers a means of restricting the mobility of the respective dye developers and of thus avoiding or reducing such desensitizing side reactions as might otherwise occur during storage of the photosensitive product.

It has been found that replacement of the dye developer, 1,4 bis-(B-[2',5'-dihydroxyphenyl]-a-methyl-ethylamino)-anthraquinone, by its hydrolyzable dye developer precursor set forth as Formula 2, in photosensitive elements prepared according to the procedure of Example 5, results in an extension of the spectral sensitivity range of the photosensitive element from 550 m to 650 m It will be noted that the liquid processing composition may, and in the above example does, contain at least one auxiliary developer, such as p-methylarninophenol [Metol], 2,4-diaminophenol [Amidol], benzylaminophenol, or a 3-pyrazolidone, such as l-phenyl-3-pyrazolidone [Phenidone]. The preferred auxiliary developer is 1- phenyl-3-pyrazolidone. This auxiliary developer serves to accelerate and possibility initiate the action of the dye developer. A portion of the dye developer may be oxidized by an energy transfer reaction with oxidized auxiliary developer.

The compounds of this invention may be used also in conventional photographic processes, such as tray or tank development of conventional photosensitive films, plates or papers containing said compounds to obtain black-andwhite, monochromatic or toned prints or negatives. By way of example, a processing composition suitable for such use may comprise an aqueous solution of approximately 1% sodium hydroxide, 2% sodium sulfite and 0.05% potassium bromide. After development is completed, any unreacted dye developer is washed out of the photosensitive element, preferably with an alkaline washing medium or other medium in which the unreacted dye developer is soluble. The expression toned is used to designate photographic images wherein the silver is retained with the precipitated dye, whereas monochromatic is intended to designate dye images free of silver.

It should be noted that the compounds of this invention are self-sufiicient to provide the desired color image and do not depend upon coupling reactions to produce the desired color. They thus provide a complete departure from conventional photographic color processes in which the color is produced by a coupling reaction involving the oxidized developing agent.

It should be noted that it is within the scope of this invention to use mixtures of the compounds to obtain a desired color.

It will be apparent that, by appropriate selection of the image-receiving element from among suitable known opaque and transparent materials, it is possible to obtain either a colored positive reflection print or a colored positive transparency. Likewise, the inventive concepts herein set forth are adaptable for multicolor work by the use of special photographic materials, for example, film materials of the type containing two or more photosensitized elements associated with an appropriate number of imagereceiving elements and adapted to be treated with one or more liquid processing compositions, appropriate dye developer hydrolyzable derivatives suitable to impart the desired subtractive colors being incorporated in the photosensitized elements.

Examples of such photographic materials are disclosed in US. Patent No. 2,647,049 to Edwin H. Land,

The inventive concepts herein set forth are also adaptable for the formation of colored images in accordance with the photographic products and processes described and claimed in the copending application of Edwin H. Land, Serial No. 448,441, filed August 9, 1954, (now US. Patent No. 2,968,554 issued December 17, 1960), and also the copending application of Edwin H. Land and Howard G. Rogers, Serial No. 565,135, filed February 13, 1956.

In the preceding portions of the specification the expression color has been frequently used. This expression is intended to include the use of a plurality of colors to obtain black, as well as the use of a single black dye developer precursor.

Since certain changes may be made in the above products and processes without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A process of forming transfer images in color which comprises the steps of exposing a photosensitive element containing a silver halide emulsion and a dye selected from the group consisting of anthraquinone dyes characterized in that they contain not less than one and not more than two groups selected from the group consisting of the carbalkoxy and carbaryloxy monoand diesters of orthoand para-dihydroxyphenyl groups and halogen and lower alkyl nuclear substituted derivatives thereof; contacting said exposed photosensitive element with an aqueous alkaline solution; thereby providing hydrolysis of said ester groups and development of the exposed silver halide emulsion; immobilizing said dye in developed areas of said photosensitive element, as a function of the pointto-point degree of exposure of said emulsion; thereby providing an imagewise distribution of mobile dye, in undeveloped areas of said photosensitive element; and transferring, by imbibition, at least a portion of said imagewise distribution of mobile dye to a superposed image-receiving element to impart thereto a dye image.

2. The process of forming transfer images in color as defined in claim 1, wherein said dye is disposed in a separate liquid-permeable layer superposed on said silver halide emulsion and an aqueous alkaline solution containing said dye in hydrolyzed form is formed by permeating said photosensitive element with an aqueous alkaline liquid capable of hydr-olyzing and solubilizing said dye.

3. The process of forming transfer images in color as defined in claim 2, wherein said aqueous alkaline liquid is introduced by being spread in a substantially uniform layer between said photosensitive element and said imagereceiving element as said elements are brought into superposed relationship.

4. A process of forming transfer images in color as defined in claim 1, wherein said hydrolyzable dye comprises 1,4-bis- [3- [2,5 '-di- (n-hexyloxycarbonyloxy phenyl] -a-methyl-ethyl-amino -anthraquinone.

5. The process of forming transfer images in color as defined in claim 1, wherein said hydrolyzable dye comprises 1,4-bisa- [2',5'-di- (n-butoxycarbonyloxy -p'l1enyl] a-methyl-ethyl-amino) -anthraquinone.

6. The process of forming transfer images in color as defined in claim 1, wherein said hydrolyzable dye comprises 1,4 bis- 3-[2,5-di-(octadecanyloxycarbonyloxy)- phenyl] -u-rnethyl-ethyl-amino -anthraquinone.

7. The process of forming transfer images in color as defined in claim 1, wherein said hydrolyzable dye comprises 1,4-bis-( 8-[2',5di-(ethoxycarbonyloxy)-phenyl-amethyl-ethyl-amino) -anthraquinone.

References Cited by the Examiner UNITED STATES PATENTS 1/1944 Dickey et al 260-376 10/ 1945 Muskat 260-463 6/1956 Salminen 96-66 7/ 1956 Yutzy 96-3 12/1956 Rogers 96-29 2/1958 Anton et al 260-376 11/ 1958 Williams 96-9 6/ 1959 Cohler et 'al. 96-29 5/ 1961 Corley 96-29 5/1961 Rogers 96-29 7/ 1962 Blout et al 96-29 FOREIGN PATENTS 2/ 1959 Australia. 8/ 1957 Belgium. 8/1957 Belgium. 1/1959 Belgium. 8/ 8 France. 12/ 195 8 Germany. 11/ 1958 Great Britain.

NORMAN G. TORCHIN, Primary Examiner.

MILTON STERMAN, PHILIP E. MANGAN,

Examiners 

1. A PROCESS OF FORMING TRANSFER IMAGES IN COLOR WHICH COMPRISES THE STEPS OF EXPOSING A PHOTOSENSITIVE ELEMENT CONTAINING A SILVER HALIDE EMULSION AND A DYE SELECTED FROM THE GROUP CONSISTING OF ANTHRAQUINONE DYES CHARACTERIZED IN THAT THEY CONTAIN NOT LESS THAN ONE AND NOT MORE THAN TWO GROUPS SELECTED FROM THE GROUP CONSISTING OF THE CARBALKOXY AND CARBARYLOXY MONO- AND DIESTERS OF ORTHO- AND PARA-DIHYDROXYPHENYL GROUPS AND HALOGEN AND LOWER ALKYL NUCLEAR SUBSTITUTED DERIVATIVES THEREOF; CONTACTING SAID EXPOSED PHOTOSENSITIVE ELEMENT WITH AN AQUEOUS ALKALINE SOLUTION; THEREBY PROVIDING HYDROLYSIS OF SAID ESTER GROUPS AND DEVELOPMENT OF THE EXPOSED SILVER HALIDE EMULSION; IMMOBILIZING SAID DYE IN DEVELOPED AREAS OF SAID PHOTOSENSITIVE ELEMENT, AS A FUNCTION OF THE POINTTO-POINT DEGREE OF EXPOSURE OF SAID EMULSION; THEREBY PROVIDING AN IMAGEWISE DISTRIBUTION OF MOBILE DYE, IN UNDEVELOPED AREAS OF SAID PHOTOSENSITIVE ELEMENT; AND TRANSFERRING, BY IMBIBITION, AT LEAST A PORTION OF SAID IMAGEWISE DISTRIBUTION OF MOBILE DYE TO A SUPERPOSED IMAGE-RECEIVING ELEMENT TO IMPART THERETO A DYE IMAGE. 